Code covered by the BSD License  

Highlights from
Joint Estimation for EPI functional MRI using Harmonic Retrieval

from Joint Estimation for EPI functional MRI using Harmonic Retrieval by Hien
Implementation of harmonic retrieval for MRI image reconstruction

[x,obj_hat]=simdata_T2star(obj,we,N1,N2,M1,M2,d1,d2,delta1,delta2,T2star);
% Description: simulates MRI data with T2* term included according to the forward model 
% Output: simulated data 'x'

% Hien M. Nguyen, University of Illinois at Urbana-Champaign
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

function [x,obj_hat]=simdata_T2star(obj,we,N1,N2,M1,M2,d1,d2,delta1,delta2,T2star);

n1=[0:N1-1];
n2=[0:N2-1].';

i = sqrt(-1);
j = sqrt(-1);

% k and r traj assume starts from origin, so we need modulation for symmetric k-space
L1 = (N1)/2;
L2 = (N2)/2;

for k=0:N2-1
    for l=0:N1-1
        obj_hat(k+1,l+1)=obj(k+1,l+1).*exp(j*2*pi*L1*l*delta1/N1).*exp(j*2*pi*L2*k*delta2/N2);
    end;
end;

for m1=0:M1-1   
    A(:,:,m1+1)=exp(-j*m1.*(we(n2+1,n1+1)*d1+2*pi*delta1*repmat(n1,N2,1)/N1)).*exp(-m1*d1./T2star(n2+1,n1+1));  % additional T2star term
end;

for m2=0:M2-1
    B(:,:,m2+1)=exp(-j*m2.*(we(n2+1,n1+1)*d2+2*pi*repmat(n2,1,N1)*delta2/N2)).*exp(-m2*d2./T2star(n2+1,n1+1));  % additional T2star term
end;

for m1=0:M1-1
    for m2=0:M2-1
        x(m2+1,m1+1)=sum(sum(obj_hat(:,:).*A(:,:,m1+1).*B(:,:,m2+1),1),2);;
    end;
end;


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